The
young will have been on individual territories by the
start of winter but the numbers of small mammals will
decline as winter sets in, making it more difficult to
locate prey. Bad weather can have a disastrous effect on
their ability to hunt, it is the time of the highest
natural mortality. The survivors will get to know their
territory and may establish several roosts which may
eventually become nest sites.

Many
barn owls remain in their territory throughout the
winter, paired with the same mate. If the weather is mild
the pair may start courting as early as February but this
not usual.